Mari the Unwonderful Witch by Asako Yuzuki

Mari is an eleven-year-old witch who loves her life. Indeed, what's not to love about spending time with her amazing mothers, hanging out with her clever friends, eating delicious food and experimenting with fashion?

But, if you ask any of the other witches in town, Mari loves her life a little too much. After all, a wonderful witch puts the needs of others, before herself. Magic should be used to help humans - not (for example . . .) creating giant donuts for you and your classmates to scoff.

But Mari doesn't care what other people think of her - and when disaster strikes her town, she'll need to convince the other witches to have the courage to break free, too, and be just as wildly unwonderful as she is.